Stannous selenide is a layered semiconductor that is a polar analogue of black phosphorus, and of great interest as a thermoelectric material. Unusually, hole doped SnSe supports a large Seebeck coefficient at high conductivity, which has not been explained to date. Angle resolved photo-emission spectroscopy, optical reflection spectroscopy and magnetotransport measurements reveal a multiple-valley valence band structure and a quasi two-dimensional dispersion, realizing a Hicks-Dresselhaus thermoelectric contributing to the high Seebeck coefficient at high carrier density. We further demonstrate that the hole accumulation layer in exfoliated SnSe transistors exhibits a field effect mobility of up to 250cm2/Vs at T=1.3K. SnSe is thus found to be a high quality, quasi two-dimensional semiconductor ideal for thermoelectric applications.
@article{arxiv.1802.08069,
title = {Quasi-two-dimensional thermoelectricity in SnSe},
author = {V. Tayari and B. V. Senkovskiy and D. Rybkovskiy and N. Ehlen and A. Fedorov and C. -Y. Chen and J. Avila and M. Asensio and A. Perucchi and P. di Pietro and L. Yashina and I. Fakih and N. Hemsworth and M. Petrescu and G. Gervais and A. Grüneis and T. Szkopek},
journal= {arXiv preprint arXiv:1802.08069},
year = {2018}
}